Universal gas constant : Ru = 8.314 kJ/(kmol K)

Absolute temperature : deg K = deg C + 273.15 K
but : 1 deg K temperature difference equals 1 deg C temperature difference

Equations for ideal gases with constant specific heats

cp = specific heat at constant pressure [kJ/(kg K)] , the amount of heat you need to raise the temperature of 1 kg of gas by 1 deg K while keeping the pressure constant despite the temperature change.

cv = specific heat at constant volume [kJ/(kg K)] , the amount of heat you need to raise the temperature of 1 kg of gas by 1 deg K while keeping the volume constant despite the temperature change.

κ = cp / cv = ratio of above specific heats.
&kappa = 1.6667 for mono-atomic ideal gases (He , Ne , Ar , Xe ...)
&kappa = 1.4000 for di-atomic ideal gases O2, N2, H2, ....

Specific gas constant has different value for different gases :
Rs = Ru / M [kJ/( kg K )]
M = molecular mass (weight) [ kg/Kmol ]

Ideal gas law :
p*V = m*Rs*T
p*V = n*Ru*T
p = pressure [N/m2]
V = volume [m3]
m = mass [kg]
T = absolute temperature [K]
n = number of moles [kmol]


Zig Herzog; hgnherzog@yahoo.com
Last revised: 01/29/10